This invention relates to methods of assembling telescopic spectacles and more particularly to a collet lens holder which is used in conjunction with a lensometer to enable one to provide spectacle correction on axis for the telescopic spectacle assembly.
As one can ascertain, there are many individuals who are visually handicapped and who require the wearing of spectacles which have incorporated therein telescopic assemblies to enable these individuals to view distant objects. There are many causes of such visual handicaps and essentially the prior art is replete with a number of devices which enhance the vision of such individuals and enable these individuals to see in a reliable manner.
In any event, such devices, as for example telescopic assemblies, are prescribed for visually handicapped individuals by practitioners. The resultant devices, as one will understand, are manufactured or built according to the prescription required. The manufacture of such devices is an extremely time consuming operation. As one can ascertain, a telescopic device is a compound optical system and requires a plurality of lenses. In order to accommodate the prescription, these lenses are inserted in a typical telescopic housing assembly so that the proper prescription is provided as to the proper magnification and lens alignment with respect to the optical axis of the telescopic assembly.
The telescopic assemblies are conventionally inserted within a spectacle lens which is supported by a normal spectacle frame, and hence the entire assembly is worn by the visually handicapped user in order to enhance his vision. Such telescopic assemblies, as indicated, are available in magnifications of 3.times., 4.times., 5.times., 6.times., 7.times. and so on. In any event, one has to provide the proper telescopic assembly with a spectacle lens according to the patient's prescription. This spectacle lens has to be optically aligned with the telescope assembly. Thus, the optical axis of the spectacle lens must be aligned with the optical axis of the telescope assembly since any misalignment, by way of skewing of the spectacle lens or the like, would render the resulting assembly unusable. As one can ascertain, the telescopic assembly in regard to magnification would be a function of the extent of damage associated with the handicapped user. As indicated, the telescopic assemblies are carried by a spectacle frame which is associated with an eye glass frame and the distance from the telescopic assembly when the patient is accommodating the frame is about fifteen millimeters. Hence the line of sight through the telescopic assembly is extremely important and all this is compensated for in the laboratory based upon measurements made by the practitioner.
For an example of such a device, reference is made to U.S. Pat. No. 4,364,645 entitled Adjustable Frame Apparatus for Telescopic Assemblies issued to William Feinbloom on Dec. 21, 1982. That patent shows a trial frame assembly which is employed for determining interpupilary distances and the angle of inclination for persons having low or reduced vision and who require such telescopic assemblies. If reference is made to that patent, one can ascertain the problems and the general nature of telescopic assemblies.
As will be described, the fabrication of such assemblies in the laboratory or at the manufacturing facility is an extremely difficult task. One employs conventional instruments such as a lensometer to enable one to properly align the spectacle lens with the telescopic assembly before permanently affixing the lens with the telescopic housing assembly. The optical center of a spectacle lens in such applications always corresponds to its geometric center. However, in inserting a spectacle lens in a telescope assembly misalignment can easily occur if the spectacle lens is inserted off center and/or skewed with respect to the optical axis of the telescope assembly. The lensometer essentially is a device which measures the focal length of lenses as well as checking for optical alignment.
A suitable example of an extremely popular lensometer is an instrument manufactured by the Bausch and Lomb Company of Rochester, N.Y. which instrument is sold under the name Vertometer and has been widely employed in the optical field. This instrument is utilized during lens assembly procedures whereby a compound lens assembly having a fixed lens is provided with additional lenses using the Vertometer for alignment and measurement of the assembly.
In this manner the operator manually orientates the spectacle lens with respect to the telescope in order to obtain proper alignment. This is done while the telescopic lens assembly is held in position along the optical axis of the Vertometer. As one can ascertain, it is an extremely difficult procedure and once the operator checks optimum alignment, he then has to secure the spectacle lens to the telescopic assembly by means of a suitable epoxy or glue. This procedure can take a skilled operator a great deal of time due to the fact that the lenses being accommodated may be small and fragile and further due to the fact that the entire procedure has to be accommodated with the use of the Vertometer.
It is therefore an object of the present invention to provide a unique method enabling one to obtain spectacle correction on axis for a telescopic lens system.
It is a further object in providing a collet device which is essentially a lens holder which device is placed over the lens stop adapter in the Vertometer to enable the operator to thereby perform adjustment in a minimum amount of time while providing extremely reliable results.